Radio-echo distance indicator including vernier means



Oct. 23, 1951 L. A. DE ROSA 2,572,014

RADIO-ECHO DISI'ANCE INDICATOR INCLUDING VERNIER MEANS Original Filed Jan. 30, 1943 2 $HEET$-SHEET l mum/nae EECEI YER flMPL/FIER nun * J 1 CL IPPEI? CIRCUIT a m K 24 f 20 as I nMPuFlER Fuse p eavsmmk SWEEP GEIIEMR AHPUFIEE nmE/vanm L I snack armsa .LLLLLL g 2 SWEEP VIBRRTOR INVENTOR. LOUIS H. ,4054

Oct. 23, 1951 L. A. DE ROSA 2,572,014

RADIO-ECHQ DISTANCE INDICATOR INCLUDING VERNIER MEANS Original Filed Jan. 30, 1943 2 SHEETS-SHEET 2 INVENTOR. LOU/8 H. 051F054 .ATZ'ORIW Patented Oct. 23, 1951 RADIO-ECHO DISTANCE INDICATOR v INCLUDING VERNIER MEANS.

Louis A. de Rosa, Bloomfield, N. J., assignor to Federal Telephone and Radio Corporation, Newark, N. J., a corporation of Delaware Continuation or application Serial No. 474,145,, January 30, 1943. This application July 8, 1947,

Serial No. 759,660

Claims. 1

This invention relates to radio detection systems such as used for detecting and determining the distance to hostile aircraft and ships.

' This application is a continuation of, and a substitute for, my copending application Serial No. 474,145, filed January 30, 1943, now abandoned. I

In my copending application Serial No. 464,008,

filed October 31, 1942, I show several embodi- -ments of radio detection systems in which I use first and second oscillographs, the first oscillograph to obtain an approximate indication or panoramic'view of the location of obstacles within a given range such as 200 miles more or less, and the second oscillograph to provide for a more accurate or vernier indication of the distance to a selected one of the obstacles detected by the first oscillograph.

It is an object of this invention to provide a method and means in addition to the methods and means disclosed in my aforesaid copending application Serial No. 464,008 for determining with a high degree of accuracy the distance to detected obstacles.

Another object of my invention is to provide a method and means to produce a narrow pulse selectively'displaced with respect to a synchronizing or main pulse.

* According to features of my invention, the se lective' displacement of the narrow pulse relative to a synchronizing or main pulse is accomplished by first generating a series of narrow pulses having" a given displacement between successive pulses, in timed relation with respect to the synchrl'z'iizing pulse. Energy of the synchronizing pulse is retarded an amount equal to a selected displacement and then is mixed with the series of narrow pulses and serves to segregate one of the series. The output of the mixing operation is so controlled as to produce an output or reference pulse similar in shape to the narrow pulses whenever one-of the'r'iarrow pulses coincides with the'retarded pulseenergy This reference pulse has the selected'displacement determined by the retardation-of the synchronizing pulse, and since it is of narrow duration, it defines more accurately the amount of retardation than the retarded pulse'energy which is rounded ofi by the retarding action. 1 I,

'Thls-method'of pulse production may be used for determining the distance'to an obstacle indicated on thescreens of cathode ray oscillographs. For example, the synchronizing pulse is synchronized with the transmission of impulses the reflections of which, caused by obstacles, produce echo pulses that appear upon the screens of the oscillographs. The series of narrow pulses produced may be applied to the first or panoramicviewing oscillograph as marker pulses, and to. the

second or vernier oscillograph to control the production of sweep potentials therefor. Thus, the second or vernier oscillograph is provided with a sweep corresponding to a. designated segment of the sweep of the first oscillograph. To determine what part or segment of the panoramic sweep that is desirable to be covered by the vernier sweep, the reference pulses produced by the mixing operation may be used to control a flip-flop type of multi-vibrator to produce a pulse of a duration equal to the time interval determined by the marker pulses on the first oscillograph. This extended pulse is then applied to the grids controlling the intensity of the beams for the two oscillographs so that the portion of the sweep of the first oscillograph corresponding to the perceptible sweep of the second oscillograph is designated by an added brilliance. In addition, a second series of pulses may be produced in timed relation with the reference pulse for calibration of the sweep of the second oscillograph, The time between transmission of an impulse and the initiation of the perceptible sweep for the second oscillograph will be determined by the amount of retardation applied to the synchronizing pulse. It will be clear, therefore, that long periods of time can be precisely measured by using a retardation means in accordance with my invention, even though the retardation of the synchronizing pulse tends to distort and round out the pulse.

.For a further understanding of the invention, reference may be had to the following detailed description to be read in connection with the accompanying drawings, in which: r

Fig. 1 is a schematic illustration of a radio detection system in accordance with myinvention, and

Fig. 2 is a graphical illustration ing features of the invention.-

. I Referring to Figs. 1 and'2, the radio detection system illustratedincludes a transmitter [0 by which impulses ll (curve a) aretransmitted over an antenna I2. ,A receiver together with a first oscillograph 2| and a secondtoscillograph 22 receive and indicate echo pulses produced by obstacles in response to the transmitted impulses of the operatl I. The receiver I is blocked by the usual blocking circuit ll controlled b y synchronizing pulses Ila tom the transmitter so as -t olprotectthe receiver during transmission or, the impulses.

3 The first oscillograph 2| is adapted to indicate approximately the location of the reflecting obstacles while the second oscillograph provides an expanded viewof a portion of the time base of the oscillograph 2|, so that vernier measurement of the distance to a particular obstacle can be made. The sweep wave of the first oscillograph is generated by a sweep generator 23 in response to the synchronizing pulses Ha, which are timed with the transmission of the impulses |l. The sweep XY of the second oscillograph is also based on the occurrence of the synchronizing pulses Ila, but may be varied to provide for perceptibility of selected portions of the range covered by the sweep AB of the first oscillograph.

For generation and control of the sweep X-Y, each synchronizing pulse Ila is amplified by an amplifier 24. This produces a negative pulse which I use to control a pulse generator 28, such as the shock-excited pulse generator disclosed in my copending applications Serial Nos. 466,557 and 467,341, filed November 23 and 30, 1942, now Patent No. 2,438,904, granted April 6, 1948, and Patent No. 2,495,704, granted January 31, 1950, respectively. The generation of pulses by either of the embodiments disclosed in these applications involves the shockexcitation of a resonant circuit, whereby a damped oscillation is produced. Means are provided to compensate for the decay of the oscillations so as 'to produce substantially constant amplitude oscillations in respect to the synchronizing pulse. These oscillations are clipped and diflerentiated to produce pulses 28 which are narrow in duration, and applicable as marker pulses for calibration purposes as indicated in connection with the deflection circuit of the first oscillograph 2|. I also ,use pulses 28 by connection 38 and 8| to control the sweep generator 32 of the second oscillograph 22. This provides a sweep, X-Y for the oscillograph 22 in response to each of the pulses 28.

In order to produce the adjustment of the perceptibility of the sweep X-Y, the pulse lib is applied to a delay line 85. This delay line may be of the type having a network of condensers and inductances arranged with outlet taps 88 so as to provide for selected retardation. The delay line is provided with an adjustable contact 38 adapted for selected engagement with the outlet taps 88. An amplifier 48 is connected to the adjustable contact 38 for amplification and clipping of the retarded pulse energy ||c as indicated between clipping levels 42 and 43 (curve b). This is desirable where the pulseis rounded because of the filtered action of the delay network. The delay line for any appreciable retardation tends to round off the pulse so that the leading edge thereof is no longer substantially vertical. By amplifying and clipping the retarded pulse, a substantially rectangular pulse shape lld (curve 0) is produced. This rectangular pulse lld is applied to a grid of a vacuum tube 58.

The pulses 28 of the generator 28 are also applied through connections 88 and 28 to a second grid 52 of the vacuum tube 58. The grids 5| and 82 are suitably biased negatively so that the pulses received independently on the grids 5| and 52 are insufficient to produce conduction between the cathode 53 and the anode 54. This is illustrated by the gate level of the tube indicated by broken line 58 in curve 0. When the retardation of the pulse lid is such that one of the pulses 28 coincides therewith, the resulting momentary conduction of the tube produces a reference pulse 28a, which is similar in shape to the pulse 28. As the retardation of the pulse energy He is varied by adjustment of the contact 88, the rectangular pulse lld will combine with successive pulses 28 to thereby vary the occurrence of the reference pulse 28a in steps according to the displacement of the pulses 28.

The reference pulse 28a is applied to a known flip-flop multl-vibrator 62 of the character adapted to flip from a first state of operation to a second in response to a pulse 28a and then to flop back to the first state of operation after a a predetermined interval adjustable to approximately the time displacement of the pulses 28. This produces an extended rectangular pulse 83. To insure substantial constant amplitude for the pulse 88. the output of the multi-vibrator 52 is applied through a clipper stage 84. The pulse 83 is applied to an electrode 86 which controls the intensity of the beam of the oscillograph 22. Thus, for the duration of the pulse 68, the beam will be increased in intensity so as to produce a through an attenuator 88 to an'electrode 12 of the oscillograph 2| whereby the beam of the oscillograph 2| is increased in intensity for the duration of the pulse 63. Since the sweep X--Y is selected for purposes of illustration ten times faster than the sweep AB,,this indication II will be 1% of the sweep AB.

The reference pulses 28a are also applied to a .shock excited pulse generator 14 similar to generator 28 to produce calibration pulses 18 for the sweep X-Y.

From an inspection of Fig. 2, the operation of the system is readily apparent. Curve a shows the panoramic sweep A-B of oscillograph 2| defiected in accordance with reflections received in response to transmission of impulses ll.

28. Curve b represents the resulting shape of synchronizing pulse ||b after it has passed through a portion of the delay line 85. After this retarded pulse He is amplified and clipped a substantially rectangular pulse ||d, curve 0 is produced. The pulse Id is mixed in tube 58 with pulses 28 and when a pulse 28 coincides with the pulse 1 Id conduction by the tube occurs, thereby producing the reference pulse 280 similar in shape to the narrow pulses 28. This reference pulse represents the setting of the contact 88 on the delay line 35. The sweep X-Y (curve e) is timed according to the pulses 28 and the perceptibility thereof is controlled by the multi-vibrator pulse 83 (curve d), which is synchronized with the reference pulse 28a. The pulse 83 also increases the brilliance of the portion 18 of the sweep AB. which corresponds to the perceptible sweep X-Y on the oscillograph 22. Thus, the perceptible sweep X--Y of the oscillograph 22 covers in expanded scale the portion of the range indicated by 18 on the sweep A-B of oscillograph 2|. By detection of the occurrence of echo pulses such as the pulse 55, for example, among the calibration pulses 15, the vernier measurement of the distance to an obstacle causing the echo pulse is obtained.

While I have disclosed a specific apparatus for producing the panoramic viewing and the vernisr measurement of distance to obstacles in accord- The sweep is also shown calibrated with marker pulses V ance with my invention, it will be understood that the form herein illustrated and described is given by way of example only and not as limiting the object of the invention and the appended claims.

I claim:

1. A method of producing a narrow pulse selectively displaced relative to a synchronizing pulse comprising generating in response to each synchronizing pulse a series of narrow pulses having a given displacement therebetween in timed relation with said synchronizing pulse, deriving a portion of energy from said synchronizing pulse, delaying said derived portion of energy to occur at a desired later time point and segregating by means of said pulse portion a given one of said series of pulses to produce an output pulse similar to said narrow pulses each time one of the narrow pulses coincides with said pulse portion.

'2. The method defined in claim 1 wherein the production of the output pulse from the segregating operation comprises limiting the effect of the segregated energy to an amplitude at least as great as the derived pulse energy whereby output energy is produced only by superposition of a narrow pulse on the derived pulse energy.

3. The method defined in claim 1 in combination with the steps of amplifying and clipping the energy of said synchronizing pulse whereby the pulse energy is translated into a substantially rectangular pulse shape before it is used for segregating one of a series of narrow pulses.

4. In a method of determining the distance to an obstacle indicated on the screen of a cathode ray beam oscillograph by an echo pulse produced by the obstacle in response to a transmitted impulse the steps of generating a series of narrow pulses having a given displacement therebetween in timed relation with said impulse, selecting one of said series of pulses as a reference pulse in accordance with a given portion of the screen to be observed, sweeping the cathode ray beam of said oscillograph across said .screen in synchronism with each of the pulses of said series, generating a pulse of a desired duration in response to said reference pulse, and applying the duration pulse to control the intensity of the beam of the oscillograph so as to render perceptible a selected portion of the sweep as determined by said dura tion pulse.

5. In a method of determining the distance to an obstacle indicated on the screens of first and second cathode ray beam oscillographs by an echo pulse produced by the obstacle in response to a transmitted impulse, the steps of generating a series of narrow pulses having a given displacement therebetween in timed relation with said impulse, selecting one of said series of pulses as a reference pulse in accordance with a given portion of the screen to be observed, producing a sweep potential for the beam of the first oscillograph in synchronism with the transmission of said impulse, producing sweep potentials for the beam of the second oscillograph in synchronism with each of the pulses of said series, generating a pulse of desired duration in response to said reference pulse, applying the duration pulse to render perceptible a selected portion of the sweep of the second oscillograph as determined by said duration pulse, and to render more brilliant the portion of the sweep of the first oscillograph corresponding to the perceptible sweep of the second oscillograph.

6. The method defined in claim 5 wherein the step of generating the duration pulse includes the step of translating said reference pulse into a substantially rectangular pulse of a duration approximately equal to the displacement between the successive pulses of said series.

'7. A system for producing a narrow pulse selectively displaced relative to a synchronizing pulse comprising a source of synchronizing pulses, means to generate in response to each pulse from said source a series of narrow pulses having a given displacement therebetween in timed relation with a given synchronizing pulse of said source, means to retard energy of said synchronizing pulse a selected multiple of said displacement, a vacuum tube to mix the retarded pulse energy with said series of pulses, and means to bias the vacuum tube so as to produce an output pulse when one of said narrow pulses coincides with said retarded pulse.

8. A system for producing a narrow pulse selectively displaced relative to a synchronizing pulse comprising a source of synchronizing pulses, means to generate a series of narrow pulses having a given displacement therebetween in timed relation with a given synchronizing pulse of said source including a resonant circuit arranged to be shock excited by said synchronizing pulses, means to retard energy of said synchronizing pulse a selected multiple of said displacement, a vacuum tube to mix the retarded pulse energy with said series of pulses, and means to bias the vacuum tube so as to produce an output pulse when one of said narrow pulses coincides with said retarded pulse.

A system for producing a narrow pulse selectively displaced relative to a synchronizing pulse comprising a source of synchronizing pulses, means to generate a series of narrow pulses having a given displacement therebetween in timed relation with a given synchronizing pulse of said source, means to retard energy of said synchronizing pulse a selected multiple of said displacement, said means for retarding having associated therewith means to amplify and clip the retarded energy so as to produce a substantially rectangular pulse shape, a vacuum tube to mix the retarded pulse energy with said series of pulses, and means to bias the vacuum tube so as to produce an output pulse when one of said narrow pulses coincides with said retarded pulse.

10. In a radio detection system having a transmitter, a receiver and at least one oscillograph for detecting the reception of an echo pulse produced in response to a transmitted impulse, the combination therewith of means for generating a series of narrow pulses having a given displacement therebetween in timed relation with said impulse, means to retard pulse energy synchronized with said impulse a selected multiple of said displacement, a vacuum tube for mixing the retarded pulse energy with said series of pulses, means to bias said tube so as to produce a reference output when one of the series of pulses coincides with said retarded pulse energy, means responsive to each of the pulses of said series to produce a sweep potential for the oscillograph, means to generate a pulse of a desired duration in response to said reference pulse, said oscillograph having a beam intensity control circuit and means to apply the duration pulse to the beam intensity control circuit of the oscillograph so as to render perceptible a sweep thereof displaced with respect to said impulse an amount equal to the retardation of said pulse energy.

11. In a radio detection system having a. transmitter, a receiver and first and second oscillographs for indicating an echo pulse produced by an obstacle in response to a transmitted impulse the combination therewith of means to generate a series of narrow pulse having a given displacement therebetween in timed relation with said impulse, means to retard pulse energy synchronized with said impulse a selected multiple of said displacement, a vacuum tube for mixing the retarded pulse energy with said series of pulses, means to bias said tube so as to produce a reference pulse output similar'in shape to said narrow pulses each time one of said narrow pulses coincides with said retarded pulse energy, means to produce a sweep potential for the first oscillograph in synchronism with the transmission ofthe said impulse, means to produce a sweep potenial for the second oscillograph in synchronism with each of the pulses of said series, means to generate a pulse of a desired duration in response to said reference pulse, said first oscillograph and said second oscillograph each having a beam intensity control circuit, means to apply the duration pulse to the beam intensity control circuit of the second oscillograph so as to render perceptible a sweep thereof displaced with respect to said impulse an amount equal to the retardation of said pulse energy, and means to apply the duration pulse to the intensity control circuit of the first oscillograph so as to render more brilliant the portion of the sweep thereof corresponding to the range covered by the sweepof said second oscillograph.

12. A method of determining the distance to an obstacle indicated on the.screens of first and second cathode ray beam oscillographs by an echo pulse produced by the obstacle in response to a transmitted impulse, comprising generating a series of narrow pulses having a given displacement therebetween in timed relation with said impulse, selecting one of said series of pulses as a reference pulse in accordance with a given porjtion of the screen to be observed producing a sweep potential for the beam of the first oscillograph in synchronism with the transmission of said impulse, producing sweep potentials for the beam of the second oscillograph in synchro j nism with each reference pulse, generating a pulse of desired duration in response to said reference pulse, applying the duration pulse to render perceptible the sweep of the second oscillograph as determined by said duration pulse, and to render more brilliant the portion of the sweep of the first oscillograph corresponding to the perceptible sweep of the second oscillograph.

13. A system for producing a narrow pulse selectively displaced relative to a synchronizing pulse comprising a source of synchronizing pulses, means to generate a series of narrow pulses having a given displacement therebetween in timed relation with a given synchronizing pulse of said source, means to retard energy of said synchronizing pulse in a plurality of fixed steps each of a selected multiple of said displacement, a vacuum tube to mix the retarded pulse energy with said series of pulses, and means to bias the vacuum tube so as to produce an output ulse when one of said narrow pulses coincides with said retarded pulse.

14. In a radio detection system having a transmitter, a receiver and at least one oscillograph for detecting the reception of an echo pulse produced in response to a transmitted impulse, the combination therewith of means for generating a series of narrow pulses having a given displacement therebetween in timed relation with said impulse, means to retard pulse energy synchronized with said impulse a selected multiple of said displacement, a vacuum tube for mixing the retarded pulse energy with said series of pulses, means to bias said tube so as to produce a reference pulse output when one of the series of pulses coincides with said retarded pulse energy,-means to produce a sweep po ential for the oscillograph for each reference pulse, means to generate a pulse of a desired duration in response to said reference pulse, said oscillograph having a beam intensity control circuit and means to apply the duration pulse to the beam intensity control circuit of the oscillograph so as to render perceptible a sweep thereof displaced with respect to said impulse an amount equal to the retardation of said pulse energy.

15'. In a radio detection system having a transmitter, a receiver and first and second oscillographs for indicating an echo pulse produced by an obstaclein response to a transmitted impulse the combination therewith of means to generate a series of narrow pulses having a givendisplacement therebetween in timed relation with said impulse, means to retard pulse energy synchroduration pulse to the beam intensity control circuit of the second oscillograph so as to render perceptible a sweep thereof displaced with respect to said impulse an amount equal to the retardation of said pulse energy, and means to apply the duration pulse to the intensity control circuit of the first oscillograph so as to render more brilliant the portion of the sweep thereof .correspondi g to the range covered by the sweep of said second oscillograph.

LOUIS A. nl: ROSA.

REFERENCES crrEn The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,355,363 Christaldi Aug. 8, 1944 2,416,088 Deerhake Feb. 18, 194:! 2,423,082 Busignies July 1, 1947 FOREIGN PATENTS Number Country Date 552,072 Great Britain Apr. 15, 1943 

